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Abstract

Twenty-two measures of color rendition have been reviewed and summarized. Each measure was computed for 401 illuminants comprising incandescent, light-emitting diode (LED) -phosphor, LED-mixed, fluorescent, high-intensity discharge (HID), and theoretical illuminants. A multidimensional scaling analysis (Matrix Stress = 0.0731, R2 = 0.976) illustrates that the 22 measures cluster into three neighborhoods in a two-dimensional space, where the dimensions relate to color discrimination and color preference. When just two measures are used to characterize overall color rendition, the most information can be conveyed if one is a reference-based measure that is consistent with the concept of color fidelity or quality (e.g., Qa) and the other is a measure of relative gamut (e.g., Qg).

J. P. Freyssinier and M. S. Rea, “Class A color classification for light sources used in general illumination,” in Proc. of Light Sources 2012: The 13th International Symposium on the Science and Technology of Lighting, June 24–29, 2012, Troy, New York, 337–338, (2012).

Other (23)

J. P. Freyssinier and M. S. Rea, “Class A color classification for light sources used in general illumination,” in Proc. of Light Sources 2012: The 13th International Symposium on the Science and Technology of Lighting, June 24–29, 2012, Troy, New York, 337–338, (2012).

Scatter plot of CCT vs. GAI illustrating that higher CCTs favor larger gamut areas. Spearman rank correlation coefficient between GAI and CCT, R2 = 0.791. R2 for the logarithmic fit shown as a black line is 0.574. The trend is similar for all measures of gamut area, including CDI, CRC84, CRC93, CSA, and FMG. Though not as pronounced as shown above, a positive trend with CCT also exists for FSCI and PI.

Plot of Qa vs. Qg. The horizontal axis is related to fidelity and is a proxy for quality or naturalness when used for general illumination. The vertical axis is a measure of relative gamut and is a proxy for preference and discrimination. Refer to Table 2 for an explanation of the abbreviations.

Tables (3)

Table 2 Matrix of Spearman Rank correlation coefficients that also illustrates blocks of similarity from the MDS scaling solution (see next secion). The upper left shading in orange █ identifies a cluster that can be called “fidelity-based” measures, the middle shading in green █ identifies a cluster that can be called “preference-based” measures, and the lower right shading in blue █ identifies a cluster that can be called “gamut-based” (discrimination) measures. The date that each index appears in the literature is also provided. ** indicates that the correlation is signification at the 0.01 level and * at the 0.05 level (2-tailed).

Metrics

Table 1

Summary of the SPDs employed in this study. Abbreviations are used in Figs. 2 and 6

Counts and Abbreviations

Type of Illuminant

Real Illuminants

Theoretical Models

Counts

Abbr.

Counts

Abbr.

LED Phosphor

130

LP-R

29

LP-T

LED Mixed

17

LM-R

51

LM-T

Fluorescent Broadband

30

FB-R

45

FL-Ta

Fluorescent Narrowband

31

FN-R

High-Intensity Discharge

31

HI-R

–

Tungsten Filament

17

TF-R

–

Blackbody Radiation

–

8

BB-T

D-Series Illuminants

–

6

DS-T

Otherb

–

6

OT-T

Table 2

Matrix of Spearman Rank correlation coefficients that also illustrates blocks of similarity from the MDS scaling solution (see next secion). The upper left shading in orange █ identifies a cluster that can be called “fidelity-based” measures, the middle shading in green █ identifies a cluster that can be called “preference-based” measures, and the lower right shading in blue █ identifies a cluster that can be called “gamut-based” (discrimination) measures. The date that each index appears in the literature is also provided. ** indicates that the correlation is signification at the 0.01 level and * at the 0.05 level (2-tailed).

RaO

Rf

Ra

R9

Qa

Qf

RCRI

Ra12

CPI

FCI94

FCI02

Qg

Qp

1965

1967

1974

1974

2010

2010

2010

2012

1974

2007

2007

2010

2009

RaO

1.000

Rf

.901**

1.000

Ra

.946**

.875**

1.000

R9

.792**

.766**

.843**

1.000

Qa

.921**

.930**

.937**

.838**

1.000

Qf

.950**

.894**

.952**

.826**

.979**

1.000

RCRI

.875**

.842**

.891**

.813**

.906**

.925**

1.000

Ra12

.815**

.750**

.830**

.787**

.885**

.883**

.837**

1.000

CPI

.588**

.799**

.607**

.701**

.714**

.610**

.614**

.497**

1.000

FCI94

.266**

.434**

.326**

.480**

.405**

.315**

.347**

.272**

.655**

1.000

FCI02

.300**

.453**

.372**

.541**

.461**

.374**

.412**

.376**

.643**

.977**

1.000

Qg

.716**

.824**

.757**

.803**

.872**

.794**

.789**

.785**

.841**

.623**

.685**

1.000

Qp

.332**

.551**

.378**

.483**

.468**

.345**

.356**

.284**

.821**

.802**

.790**

.739**

1.000

MCRI

.581**

.723**

.646**

.746**

.751**

.685**

.748**

.696**

.778**

.637**

.710**

.891**

.638**

CDI

.016

.105*

.024

.100*

.061

.013

.038

.079

.300**

-.153**

-.131**

.255**

.272**

FMG

-.003

.0816

.000

.075

.034

-.011

.015

.050

.272**

-.189**

-.169**

.216**

.237**

CRC84

-.060

.0537

-.059

-.005

-.039

-.081

-.044

-.099*

.266**

-.175**

-.189**

.134**

.242**

CRC93

.044

.084

.053

.123*

.094

.071

.097

.195**

.179**

-.236**

-.186**

.243**

.116*

CSA

-.032

.0089

-.041

.0057

-.023

-.046

-.028

.0259

.135**

-.351**

-.326**

.102*

.0636

GAI

.016

.105*

.023

.099*

.061

.013

.037

.078

.300**

-.154**

-.133**

.254**

.272**

PI

.579**

.539**

.570**

.494**

.553**

.573**

.572**

.537**

.444**

.012

.032

.539**

.244**

FSCI

.319**

.204**

.322**

.253**

.307**

.332**

.263**

.489**

.009

-.382**

-.308**

.221**

-.125*

CCT

-.081

-.126*

-.110*

-.102*

-.134**

-.111*

-.102*

-.057

-.104*

-.564**

-.548**

-.126*

-.240**

MCRI

CDI

FMG

CRC84

CRC93

CSA

GAI

PI

FSCI

CCT

2010

1972

1977

1984

1993

1997

2004*

1986

2004

MCRI

1.000

CDI

.240**

1.000

FMG

.209**

.996**

1.000

CRC84

.145**

.943**

.953**

1.000

CRC93

.259**

.945**

.946**

.874**

1.000

CSA

.0978

.966**

.977**

.927**

.951**

1.000

GAI

.238**

1.000**

.996**

.944**

.944**

.966**

1.000

PI

.495**

.591**

.575**

.514**

.602**

.553**

.591**

1.000

FSCI

.0765

.485**

.487**

.341**

.594**

.548**

.485**

.460**

1.000

CCT

-.102*

.790**

.816**

.777**

.818**

.908**

.791**

.471**

.543**

1.000

Table 3

Performance of some of the 401 illuminants studied.

Source Type

Description

CCT

Ra

Qa

Qg

Tungesten Filament

Sylvania Tru Aim MR16 Halogen

2776

100

100

100

Tungesten Filament

Philips 75W Halogena

2836

100

100

100

LED Phosphor Real

Xicato XSM Artist 3000 K

2940

97

98

101

LED Phosphor Real

Soraa Vivid MR16 2700 K

2724

96

95

100

LED Phosphor Real

Soraa Vivid MR16 3000 K

2969

96

95

101

Fluorescent Broadband

CIE F8

4997

96

97

100

Fluorescent Broadband

F32T8/TL930

2908

95

94

102

Fluorescent Broadband

F40/C75

7412

93

95

100

HID

MHC100UMP4K

4256

92

93

101

Tungesten Filament

Solux halogen

4144

90

91

92

LED Phosphor Real

Xicato XSM 80 3000 K

2496

88

81

105

Fluorescent Broadband

F40/CWX

4030

87

85

99

HID

White SON HPS

2760

87

85

107

Fluorescent Narrowband

F32T8/TL850

5072

86

86

102

Fluorescent Narrowband

F32T8/TL835

3480

86

85

102

LED Mixed Real

GE SoftWhite LED

2976

86

84

100

Fluorescent Narrowband

F32T8TL830

2940

85

84

102

Fluorescent Narrowband

F32T8TL835

3700

85

84

102

Fluorescent Narrowband

F32T8TL841

4194

83

84

99

LED Phosphor Real

Philips EnduraLED 10W MR16 2700K

2789

82

82

97

LED Phosphor Real

Soraa Premium MR 16 3000 K

3005

82

82

96

LED Phosphor Real

Philips EnduraLED 10W MR16 3000K

3167

81

82

96

LED Phosphor Real

Soraa Premium MR16 2700 K

2708

80

81

94

Tungesten Filament

Neodimium Incandescent

2757

77

90

115

Fluorescent Narrowband

F32T8/TL741

4663

70

73

84

HID

H38JA100DX

4037

68

49

110

HID

C100S54C

2171

64

68

88

Fluorescent Broadband

Cool White FL

4290

63

63

80

HID

Topanga Plasma 5500 K

6197

63

66

72

HID

MH100W

3923

55

55

77

Fluorescent Broadband

F34T12/LW/RS/EW

4165

50

50

72

Tables (3)

Table 1

Summary of the SPDs employed in this study. Abbreviations are used in Figs. 2 and 6

Counts and Abbreviations

Type of Illuminant

Real Illuminants

Theoretical Models

Counts

Abbr.

Counts

Abbr.

LED Phosphor

130

LP-R

29

LP-T

LED Mixed

17

LM-R

51

LM-T

Fluorescent Broadband

30

FB-R

45

FL-Ta

Fluorescent Narrowband

31

FN-R

High-Intensity Discharge

31

HI-R

–

Tungsten Filament

17

TF-R

–

Blackbody Radiation

–

8

BB-T

D-Series Illuminants

–

6

DS-T

Otherb

–

6

OT-T

Table 2

Matrix of Spearman Rank correlation coefficients that also illustrates blocks of similarity from the MDS scaling solution (see next secion). The upper left shading in orange █ identifies a cluster that can be called “fidelity-based” measures, the middle shading in green █ identifies a cluster that can be called “preference-based” measures, and the lower right shading in blue █ identifies a cluster that can be called “gamut-based” (discrimination) measures. The date that each index appears in the literature is also provided. ** indicates that the correlation is signification at the 0.01 level and * at the 0.05 level (2-tailed).